The present invention relates to apparatus for inspecting wafers, and more particularly to such an apparatus using a robot arm to manipulate a wafer from an incoming position to an inspection position.
When wafers are processed to define features on the wafer, with photolithographic patterns, for example, it is customary to inspect the features to assure that they are correctly made. Inspection typically occurs several times during such processing. In the semiconductor arts, for example, semiconductor wafers are repeatedly inspected during processing to determine, for instance, whether semiconductor junction patterns or other features have been correctly formed on the wafers, and whether harmful contaminants have collected on the wafers.
Technicians are customarily employed to inspect wafers during processing. In common practice, a technician transports a wafer from an incoming position to a viewing area of a microscope. The wafer is placed feature-side up, which is conventional for microscope viewing. After inspection, the technician moves the wafer to a respective outgoing position for acceptable wafers or rejected wafers, for example. Problems arise with this practice, since even if the technician inspects the wafers in a specially prepared clean room, contaminants from the technician's hair or clothes can find their way to the wafers. Such contaminants may be viewed as flaws and cause unnecessary rejection of wafer.
Such conventional inspection of wafers by technicians is also labor intensive.